1. Field of the Invention
The present invention generally relates to a friction clutch, in particular for motor vehicles, wherein such a clutch may typically include: a driving portion as counterpressure plate; a pressure plate oriented so that it can move axially but not rotationally with respect to the counterpressure plate; a clutch plate with clutch linings which can be fixed between the counterpressure plate and pressure plate, and which is located non-rotationally on a drive shaft. Typically, the clutch plate can be provided, if necessary, with a load and/or idle damper. Typically, there may also be pressure elements for the clutch plate and/or the dampers.
2. Background Information
Known (e.g. from German Laid Open Patent Application No. 40 31 762 and German Laid Open Patent Application No. 40 40 592) are friction clutches such as those described above, on which the clutch plates are provided with torsion damping devices, between a driving side and a driven side, to suppress torsional vibrations. These torsion damping devices can be designed as single-stage or multiple-stage devices, whereby each damping stage, as a rule, tends to be constituted by the parallel connection of a spring actuator (rigidity) with a friction device (damping). The friction devices are usually based on the principle of Coulomb friction (dry friction), i.e. the moment of friction is generated by means of the relative motion between a friction element and the driving side and/or the driven side of the clutch plate. The moment of friction tends largely to be independent of the relative velocity between the two bodies participating in the generation of the friction. The level of the moment of friction generated is not only generally a function of the coefficient of friction and the radius of friction, but also of the level of the contact force of the friction element against the friction partner. This force is conventionally generated by means of a spring actuator, e.g. by a plate spring or an annular spring. The level of the contact force is usually determined by the force-displacement characteristic and thus by the position in which the spring is installed. Thus, the level of the contact force also tends to be subject to the manufacturing tolerances of all of the components which define the installation space, as well as to the bending of the plate under the force of the spring. For this reason, it is generally only possible to realize a relatively broad range of tolerances for the moment of friction. In addition to generating the contact force for the friction device, the spring is also often used for the axial restraint, or bracing, of the driving side and the driven side of the clutch plate.